Modification of the interlayer pore structure of silica iron oxide sol pillared clay using organic templates

Abstract

A novel route for modifying the interlayer pore structure of silica iron oxide sol particle pillared montmorillonite was proposed based on the post-intercalation of organic templates. The pristine mixed oxide sol pillared montmorillonite (SFM) was prepared by the reaction of Na-montmorillonite with silica iron sol particles obtained by depositing iron hydroxy cations on hydrolyzed silica sol surfaces. Three kinds of surfactant molecules with different molecular geometries and sizes were subsequently introduced between the interlayer spaces of the oxide sol exchanged montmorillonite. Upon intercalating the organic templates, a part of the interlayer sol particles was replaced and rearranged by the templates. Removing the templates by calcination at 550 °C resulted in the mesoporous sol pillared clays with controlled pore structures. The porous characteristics of the modified pillared clays were analyzed in detail using nitrogen and some selected solvent adsorption–desorption isotherms, which exhibited extremely large BET surface areas up to 750 m² g^–1 and enlarged pore sizes of >20 Å.